Asymmetric Digital Subscriber Line (ADSL) is a modem technology that uses a special ADSL modem to convert existing twisted-pair telephone lines into access paths for multimedia and high-speed data communications. ADSL allows more data to be sent over existing copper telephone lines (POTS) and can expand existing access capacity by a factor of 50 or more without new cabling. ADSL can transform a public information network from one limited to voice, text and low resolution graphics to a powerful system capable of carrying multimedia, including full motion video, to subscribers. ADSL allows telephone companies, and other service providers, to enter new markets for delivering information in video and multimedia formats to subscribers in areas where broadband cabling is not available. The increased data capacity provided by ADSL technology can be used to transmit movies, television, video catalogs, remote CD-ROMs, corporate LANs, and the Internet into homes and small businesses. The high capacity ADSL lines are sensitive to stray signals and require reliable and effective bonding and grounding in order to operate properly.
An ADSL circuit connects an ADSL modem on each end of a twisted-pair telephone line, creating three information channels: a high speed downstream channel, a medium speed duplex channel (depending on the implementation of the ADSL architecture), and a POTS (plain old telephone service) or an ISDN (integrated services digital network) channel. The POTS/ISDN channel is split off from the digital modem by filters, thus guaranteeing uninterrupted POTS/ISDN, even if the ADSL fails. Each channel can be sub-multiplexed to form multiple, lower rate channels, depending on the system.
The large amount of data transmitted by ADSL and the high transmission speeds requires the transmission lines to operate at maximum efficiency. Accordingly, the bonding and grounding of the RF drain wire and the internal shield of an ADSL multi-pair cable are critical. The prior art devices used for bonding and shielding the RF drain wire and internal shield in a cable have been found to be unsatisfactory for several reasons. For example, many prior art devices include a small triangular bullet style bond. These devices force the bond under the cable jacket where the bond is hidden from view and cannot be inspected. In addition, forcing the bond under the jacket can cause the shield to be pushed back into the jacket so that there is not sufficient metal-to-metal contact.
In addition, many of the prior art devices use a stranded daisy chain arrangement with pre-set eyelets which are either too bulky or too costly or have an oversized load capacity. These devices are not versatile due to their pre set holes, which limit the choices of location for securing the new bonded drop or bond. Moreover, the prior art devices are not tightly secured to the cable and can be easily pulled out of the cable jacket. Accordingly, there is a need for a bonding and grounding clamp that can be easily connected to multi-pair cables, such as ADSL cables, and provide reliable and effective bonding and grounding of the RF drain wire and the internal shield.
Another object of the present invention is to provide a grounding clamp for a shielded cable that does not damage the wires inside the cable when the clamp is secured to the cable. Grounding clamps for the shields of multiple conductor cables that are currently in use are installed over the cable and then tightened to secure the clamp in place and to provide good electrical contact between the clamp and the shield. However, installing the clamp around the cable can damage the wires if the clamp is tightened too much. This can split open the covers around the wires and cause them to come in contact with each other. In some cases, it can even result in one or more of the wires being crushed or severed. Accordingly, there is a need for a bonding and grounding clamp assembly that can be easily connected to multi-pair cables, such as ADSL cables, and provide reliable and effective bonding and grounding of the RF drain wire and the internal shield without damaging the wires.